Hypertrophic Osteopathy Concurrent with an Aberrant Right Subclavian Artery in a Dog

A 13-year-old spayed female cocker spaniel was presented with a 2-month history of swelling in several digits and intermittent hindlimb lameness. Radiographs revealed marked soft-tissue swelling and periosteal new bone formation without cortical bone destruction, characteristic of hypertrophic osteopathy (HO), in the distal parts of all extremities except for the right forelimb. However, no notable findings were detected in thoracic radiographs. An ultrasonography indicated cranial bladder wall thickening, which resolved following antibiotic therapy. Computed tomographic angiography identified a potential underlying cause as an aberrant right subclavian artery (ARSA) originating from the aortic arch, compressing the esophagus and causing mild esophageal cranial dilation to the aberrant vessel. No other intrathoracic or neoplastic lesions were observed. Gastrointestinal symptoms, such as regurgitation, were absent. Although an ARSA was likely the cause of HO, surgical correction was declined by the owner. To the best of our knowledge, this is the first reported case of HO concurrent with ARSA in dogs.